The present invention relates to a vehicle frame and, more particularly, to a rear frame axle suspension.
Vehicles currently have rear frame axle suspensions that allow a rear axle of the vehicle to move vertically relative to the vehicle. Rear tires and the rear axle of the vehicle can therefore travel over bumps in the road without fully transferring the vertical movement from the rear tires and the rear axle to passengers in the vehicle. The rear axle of the vehicle also has shock absorbers that dampen the vertical movement of the axle, thereby damping any vertical force from the rear axle and providing for a smoother ride for the passengers in the vehicle.
Heretofore, rear frame axle suspensions 1 (see FIG. 1) have included a pair of rear frame rails 2 that converge towards the rear of the vehicle. Each of the rear frame rails 2 typically has included a pair of side shackles 3 connected to outside faces 4 of the rear frame rails 2. The pair of shackles 3 retain the leaf springs 5 parallel to the rear frame rails 2. The leaf springs 5 are also connected to a rear axle housing 6 encasing the rear axle (not shown) by U-bolts 9. The leaf springs 5 are not perpendicular to the rear axle housing 6. The leaf springs 5 allow for relative movement between the rear axle housing 6 and the body and frame of the vehicle. However, since the leaf springs 5 are not perpendicular to the rear axle housing 6, the movement of the rear axle housing 6 causes a side load on the leaf springs 5 and the U-bolts 9. Additionally, shock absorbers 7 have typically been connected to the rear axle housing 6 inboard of the rear frame rails 2 and to inside faces 8 of the rear frame rails 2 to dampen the vertical movement of the vehicle. The shock absorbers 7 dampen any vertical force transferred from the rear axle housing 6 to the rear frame rails 2.
One aspect of the present invention is to provide a rear frame axle suspension comprising a pair of rear frame rails having a front bracket and a rear bracket connected thereto. Each front bracket is connected to a bottom of the rear frame rails and each rear bracket is connected to an outside face of the rear frame rails. A pair of leaf springs are connected at a front end to the front bracket and at a rear end to the rear bracket of each rear frame rail. The leaf springs have a longitudinal direction between the front bracket and the rear bracket. The leaf springs are nonparallel to the rear frame rails. An axle housing is connected to the leaf springs, with the axle housing being adapted to contain at least one axle having an axis of rotation perpendicular to the longitudinal direction of the leaf springs. The rear frame axle suspension also includes a pair of shock absorbers. Each shock absorber is connected to one of the rear frame rails at a first connection point and to the axle housing at a second connection point, with the rear frame rails being located between the first connection points.
Another aspect of the present invention is to provide a rear frame axle suspension including a pair of rear frame rails, each rear frame rail including an outside face, an inside face, a bottom face and a top face. A front bracket and a rear bracket are attached to each rear frame rail. A pair of leaf springs are each connected at a front end to the front bracket at a front end bracket connection point and at a rear end to the rear bracket at a rear end bracket connection point for each rear frame rail. Each leaf spring has a longitudinal direction between the front bracket and the rear bracket, with the longitudinal direction of each leaf spring being non-parallel to the rear frame rails. Each rear frame rail includes a notch extending between the outside face of the rear frame rails and the bottom face of the rear frame rails. The notches allow the leaf spring to rise to a level above the bottom face of the rear frame rails during jounce.
Yet another aspect of the present invention is to provide a vehicle frame including a pair of frame rails, with each rear frame rail having an outside face, an inside face, a bottom face and a top face. A front bracket is connected to each rear frame rail, with each front bracket being connected to the bottom face of the rear frame rails. A rear bracket is connected to each rear frame rail, with each rear bracket being connected to the outside face of the rear frame rails. A pair of leaf springs are each connected at a front end to the front bracket at a front end bracket connection point and at a rear end to the rear bracket at a rear end bracket connection point. The leaf springs have a longitudinal direction between the front bracket and the rear bracket, with the longitudinal direction of the leaf springs being non-parallel to the rear frame rails. An axle housing is connected to the leaf springs, with the axle housing being adapted to contain at least one axle having an axis of rotation perpendicular to the longitudinal direction of the leaf springs. The rear frame axle suspension also includes a pair of shock absorbers. Each shock absorber is connected to one of the rear frame rails at a first connection point and to the axle housing at a second connection point, with the rear frame rails being located between the first connection points. The frame rails each include a notch extending between the outside face of the frame rails and the bottom face of the frame rails. The notches allow the leaf springs to rise to a level above the bottom face of the rear frame rails during jounce.
Accordingly, the vehicle suspension provides for a more durable suspension and a longer life for the leaf springs. Furthermore, the vehicle suspension provides for an increased roll ratio compared to the prior art roll ratio for roll damping of the vehicle. The vehicle suspension is efficient in use, economical to manufacture, capable of a long operable life, and particularly adapted for the proposed use.